You're lacking of level 1 or 2 skills.

Try relogging? :f6: I dunno, did the game prompt you with a message when you added that 1 SP into the 1st job skill?

You can try using the ticket system also...

EDIT: nvm, you need to spend 121 points on 2nd job skills. Since you only have to use 120, you'll need to dump that 1 SP into a 1st job skill.